The use of dish antennas is on the rise since their invention in 1888. In other words, with the advancements in technology, these antennas are being used for a wide variety of purposes. The parabolic dish antennas can now be used in the majority of urban areas as well. These antennas are growing in popularity due to the launch of satellite dish TV. As a matter of fact, these antennas have a lot of other significant applications.
Parabolic antennas are defined as antennas that make use of curved surfaces or parabolic reflectors with cross-sectional designs for directing radio waves. Usually, these antennas feature dish-like shapes. They have high power and capable of directing radio waves in thin beams or pick up waves in just one direction. In other words, they work like search lights or flashlights.
These high gain antennas are used for point-to-point communication as well. Their high power lets us use them for tons of purposes. For example, they can be deployed for microwave radio relay links, meaning they are capable of sending or receiving radio signals among different cities.
Parabolic Dish Antenna also work as radar antennas, transmitting narrow beams for locating huge objects like guided missiles, airplanes and ships. For satellite, spacecraft and data communication, they are used for WLAN/WAN links.
A Parabolic Dish Antenna comes with a little feed antenna and a metal reflector. The feed antenna is located at the reflector’s focus pointing backwards. Generally, reflectors are metallic surfaces made into parabolic figures. The feed antenna receives radio frequency (RF) currents via transmission line cords from transmitters. Then these currents are transformed into radio waves, which are sent back to the parabolic dish via the feed antenna. Eventually, they are reflected from the dish into beams that are parallel. Incoming waves reflect off the receiving antenna focusing on the feed antenna. So, this process converts the waves into current. Then a radio picks up these waves via a transmission line.
We can categorize parabolic dish antennas based on their shapes. Below is the description of these antennas with different shapes.
Cylindrical antennas: these antennas have reflectors that are curved in one direction and flat in the other. The curved ends of the reflectors are covered with flat plates. The purpose of the covering is to prevent radiation emission from the ends.
Shape beamed antennas: The purpose of these antennas is to generate beams of intended shape. So, they produce wide beams.
Shaped reflectors: Antennas with shaped reflectors are non-cylindrical in shape. Generally, these designs work well in radar antennas.
Shrouded dish: In this shape, a metal shield is connected to the rim of the cylindrical dish. The role of the shield is to protect the antenna against the radiation around the axis of the beam.
Lastly, parabolic antennas are also categorized based on their feeds, such as axial feed, off-axis feed and cassegrain. So, this was a concise description of parabolic dish antenna applications and how these antennas can be broken down into different categories.